Zhang Yun-Yan, Fan Guang-Han, Yin Yi-An, Yao Guang-Rui
Institute of Opto-Electronic Materials and Technology, South China Normal University, Guangzhou 510631, China.
Opt Express. 2012 Jan 2;20(1):A133-40. doi: 10.1364/oe.20.00a133.
In this study, the characteristics of the nitride-based blue light-emitting diode (LED) without an electron-blocking layer (EBL) are analyzed numerically. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency (IQE) are investigated. The simulation results indicate that the LED without an EBL has a better hole-injection efficiency and smaller electrostatic fields in its active region over the conventional LED with an AlGaN EBL. The simulation results also show that the LED without an EBL has severe efficiency droop. However, when the special designed p-type doped InGaN QW barriers are used, the efficiency droop is markedly improved and the electroluminescence (EL) emission intensity is greatly enhanced which is due to the improvement of the hole uniformity in the active region and small electron leakage.
在本研究中，对无电子阻挡层（EBL）的氮化物基蓝光发光二极管（LED）的特性进行了数值分析。研究了发射光谱、量子阱（QW）中的载流子浓度、能带图、静电场和内量子效率（IQE）。模拟结果表明，与具有AlGaN EBL的传统LED相比，无EBL的LED具有更好的空穴注入效率，且其有源区的静电场更小。模拟结果还表明，无EBL的LED存在严重的效率 droop。然而，当使用特殊设计的p型掺杂InGaN QW势垒时，效率 droop得到显著改善，电致发光（EL）发射强度大大增强，这是由于有源区中空穴均匀性的改善和小的电子泄漏。
